Today is a very sad day in our little world. It's been reported that Arthur C. Clarke, among the most influential visionaries in technology and a personal hero of Engadget readers and editors both, has died in hospital care at the age of 90. Along with his many written works (such as the infamous and immeasurably influential 2001: A Space Odyssey), Clarke was possibly best known for conceptualizing the geostationary communications satellite -- clearly one of the most important technological innovations in history.